Predstavljam vašoj pažnji tutorijal za generisanje pristupa Kubernetes klasteru koristeći Dex, dex-k8s-authenticator i GitHub.
Lokalni meme iz Kubernetes chata na ruskom jeziku
Uvod
Koristimo Kubernetes za kreiranje dinamičnih okruženja za razvojni i QA tim. Dakle, želimo im dati pristup klasteru i za kontrolnu ploču i za kubectl. Za razliku od OpenShift-a, vanilla Kubernetes nema izvornu autentifikaciju, pa za to koristimo alate treće strane.
U ovoj konfiguraciji koristimo:
- — web aplikacija za generisanje kubectl konfiguracije
- — OpenID Connect provajder
- GitHub - jednostavno zato što koristimo GitHub u našoj kompaniji
Pokušali smo koristiti Google OIDC, ali nažalost da ih započnemo sa grupama, tako da nam je integracija sa GitHub-om sasvim odgovarala. Bez grupnog mapiranja, neće biti moguće kreirati RBAC politike zasnovane na grupama.
Dakle, kako naš Kubernetes proces autorizacije funkcionira u vizualnom prikazu:
Proces autorizacije
Malo više detalja i tačku po tačku:
- Korisnik se prijavljuje na dex-k8s-authenticator (
login.k8s.example.com) - dex-k8s-authenticator prosljeđuje zahtjev Dexu (
dex.k8s.example.com) - Dex preusmjerava na stranicu za prijavu na GitHub
- GitHub generiše potrebne informacije o autorizaciji i vraća ih u Dex
- Dex prosljeđuje primljene informacije dex-k8s-authenticatoru
- Korisnik prima OIDC token od GitHub-a
- dex-k8s-authenticator dodaje token u kubeconfig
- kubectl prosljeđuje token KubeAPIServeru
- KubeAPIServer vraća pristup kubectl-u na osnovu proslijeđenog tokena
- Korisnik dobija pristup iz kubectl
Pripremne radnje
Naravno, već imamo instaliran Kubernetes klaster (k8s.example.com), a također dolazi s unaprijed instaliranim HELM-om. Imamo i organizaciju na GitHubu (super-org).
Ako nemate HELM, instalirajte ga .
Prvo moramo postaviti GitHub.
Idite na stranicu postavki organizacije, (https://github.com/organizations/super-org/settings/applications) i kreirajte novu aplikaciju (Authorized OAuth App):
Kreiranje nove aplikacije na GitHub-u
Popunite polja potrebnim URL-ovima, na primjer:
- URL početne stranice:
https://dex.k8s.example.com - URL za povratni poziv autorizacije:
https://dex.k8s.example.com/callback
Budite oprezni sa vezama, važno je da ne izgubite kose crte.
Kao odgovor na popunjen obrazac, GitHub će generirati Client ID и Client secret, čuvajte ih na sigurnom mjestu, bit će nam korisni (npr za čuvanje tajni):
Client ID: 1ab2c3d4e5f6g7h8
Client secret: 98z76y54x32w1
Pripremite DNS zapise za poddomene login.k8s.example.com и dex.k8s.example.com, kao i SSL certifikati za ulaz.
Kreirajmo SSL certifikate:
cat <<EOF | kubectl create -f -
apiVersion: certmanager.k8s.io/v1alpha1
kind: Certificate
metadata:
name: cert-auth-dex
namespace: kube-system
spec:
secretName: cert-auth-dex
dnsNames:
- dex.k8s.example.com
acme:
config:
- http01:
ingressClass: nginx
domains:
- dex.k8s.example.com
issuerRef:
name: le-clusterissuer
kind: ClusterIssuer
---
apiVersion: certmanager.k8s.io/v1alpha1
kind: Certificate
metadata:
name: cert-auth-login
namespace: kube-system
spec:
secretName: cert-auth-login
dnsNames:
- login.k8s.example.com
acme:
config:
- http01:
ingressClass: nginx
domains:
- login.k8s.example.com
issuerRef:
name: le-clusterissuer
kind: ClusterIssuer
EOF
kubectl describe certificates cert-auth-dex -n kube-system
kubectl describe certificates cert-auth-login -n kube-system
ClusterIssuer s naslovom le-clusterissuer bi već trebao postojati, ali ako ne, kreirajte ga pomoću HELM-a:
helm install --namespace kube-system -n cert-manager stable/cert-manager
cat << EOF | kubectl create -f -
apiVersion: certmanager.k8s.io/v1alpha1
kind: ClusterIssuer
metadata:
name: le-clusterissuer
namespace: kube-system
spec:
acme:
server: https://acme-v02.api.letsencrypt.org/directory
email: [email protected]
privateKeySecretRef:
name: le-clusterissuer
http01: {}
EOFKonfiguracija KubeAPIServera
Da bi kubeAPIServer radio, morate konfigurirati OIDC i ažurirati klaster:
kops edit cluster
...
kubeAPIServer:
anonymousAuth: false
authorizationMode: RBAC
oidcClientID: dex-k8s-authenticator
oidcGroupsClaim: groups
oidcIssuerURL: https://dex.k8s.example.com/
oidcUsernameClaim: email
kops update cluster --yes
kops rolling-update cluster --yesKoristimo za postavljanje klastera, ali ovo funkcionira slično za .
Dex konfiguracija i dex-k8s-autentikator
Da bi Dex radio, morate imati certifikat i ključ od Kubernetes mastera, hajde da ga uzmemo odatle:
sudo cat /srv/kubernetes/ca.{crt,key}
-----BEGIN CERTIFICATE-----
AAAAAAAAAAABBBBBBBBBBCCCCCC
-----END CERTIFICATE-----
-----BEGIN RSA PRIVATE KEY-----
DDDDDDDDDDDEEEEEEEEEEFFFFFF
-----END RSA PRIVATE KEY-----Hajde da klonimo dex-k8s-authenticator spremište:
git clone [email protected]:mintel/dex-k8s-authenticator.git
cd dex-k8s-authenticator/Koristeći datoteke vrijednosti, možemo fleksibilno konfigurirati varijable za naše .
Hajde da opišemo konfiguraciju za Dex:
cat << EOF > values-dex.yml
global:
deployEnv: prod
tls:
certificate: |-
-----BEGIN CERTIFICATE-----
AAAAAAAAAAABBBBBBBBBBCCCCCC
-----END CERTIFICATE-----
key: |-
-----BEGIN RSA PRIVATE KEY-----
DDDDDDDDDDDEEEEEEEEEEFFFFFF
-----END RSA PRIVATE KEY-----
ingress:
enabled: true
annotations:
kubernetes.io/ingress.class: nginx
kubernetes.io/tls-acme: "true"
path: /
hosts:
- dex.k8s.example.com
tls:
- secretName: cert-auth-dex
hosts:
- dex.k8s.example.com
serviceAccount:
create: true
name: dex-auth-sa
config: |
issuer: https://dex.k8s.example.com/
storage: # https://github.com/dexidp/dex/issues/798
type: sqlite3
config:
file: /var/dex.db
web:
http: 0.0.0.0:5556
frontend:
theme: "coreos"
issuer: "Example Co"
issuerUrl: "https://example.com"
logoUrl: https://example.com/images/logo-250x25.png
expiry:
signingKeys: "6h"
idTokens: "24h"
logger:
level: debug
format: json
oauth2:
responseTypes: ["code", "token", "id_token"]
skipApprovalScreen: true
connectors:
- type: github
id: github
name: GitHub
config:
clientID: $GITHUB_CLIENT_ID
clientSecret: $GITHUB_CLIENT_SECRET
redirectURI: https://dex.k8s.example.com/callback
orgs:
- name: super-org
teams:
- team-red
staticClients:
- id: dex-k8s-authenticator
name: dex-k8s-authenticator
secret: generatedLongRandomPhrase
redirectURIs:
- https://login.k8s.example.com/callback/
envSecrets:
GITHUB_CLIENT_ID: "1ab2c3d4e5f6g7h8"
GITHUB_CLIENT_SECRET: "98z76y54x32w1"
EOF
I za dex-k8s-authenticator:
cat << EOF > values-auth.yml
global:
deployEnv: prod
dexK8sAuthenticator:
clusters:
- name: k8s.example.com
short_description: "k8s cluster"
description: "Kubernetes cluster"
issuer: https://dex.k8s.example.com/
k8s_master_uri: https://api.k8s.example.com
client_id: dex-k8s-authenticator
client_secret: generatedLongRandomPhrase
redirect_uri: https://login.k8s.example.com/callback/
k8s_ca_pem: |
-----BEGIN CERTIFICATE-----
AAAAAAAAAAABBBBBBBBBBCCCCCC
-----END CERTIFICATE-----
ingress:
enabled: true
annotations:
kubernetes.io/ingress.class: nginx
kubernetes.io/tls-acme: "true"
path: /
hosts:
- login.k8s.example.com
tls:
- secretName: cert-auth-login
hosts:
- login.k8s.example.com
EOFInstalirajte Dex i dex-k8s-authenticator:
helm install -n dex --namespace kube-system --values values-dex.yml charts/dex
helm install -n dex-auth --namespace kube-system --values values-auth.yml charts/dex-k8s-authenticatorProvjerimo funkcionalnost servisa (Dex bi trebao vratiti kod 400, a dex-k8s-authenticator bi trebao vratiti kod 200):
curl -sI https://dex.k8s.example.com/callback | head -1
HTTP/2 400
curl -sI https://login.k8s.example.com/ | head -1
HTTP/2 200RBAC konfiguracija
Kreiramo ClusterRole za grupu, u našem slučaju s pristupom samo za čitanje:
cat << EOF | kubectl create -f -
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: cluster-read-all
rules:
-
apiGroups:
- ""
- apps
- autoscaling
- batch
- extensions
- policy
- rbac.authorization.k8s.io
- storage.k8s.io
resources:
- componentstatuses
- configmaps
- cronjobs
- daemonsets
- deployments
- events
- endpoints
- horizontalpodautoscalers
- ingress
- ingresses
- jobs
- limitranges
- namespaces
- nodes
- pods
- pods/log
- pods/exec
- persistentvolumes
- persistentvolumeclaims
- resourcequotas
- replicasets
- replicationcontrollers
- serviceaccounts
- services
- statefulsets
- storageclasses
- clusterroles
- roles
verbs:
- get
- watch
- list
- nonResourceURLs: ["*"]
verbs:
- get
- watch
- list
- apiGroups: [""]
resources: ["pods/exec"]
verbs: ["create"]
EOFKreirajmo konfiguraciju za ClusterRoleBinding:
cat <<EOF | kubectl create -f -
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: dex-cluster-auth
namespace: kube-system
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: cluster-read-all
subjects:
kind: Group
name: "super-org:team-red"
EOFSada smo spremni za testiranje.
Testovi
Idite na stranicu za prijavu (https://login.k8s.example.com) i prijavite se koristeći svoj GitHub račun:
Stranica za prijavu
Stranica za prijavu je preusmjerena na GitHub
Slijedite generirana uputstva za pristup
Nakon kopiranja sa web stranice, možemo koristiti kubectl za upravljanje našim resursima klastera:
kubectl get po
NAME READY STATUS RESTARTS AGE
mypod 1/1 Running 0 3d
kubectl delete po mypod
Error from server (Forbidden): pods "mypod" is forbidden: User "[email protected]" cannot delete pods in the namespace "default"
I funkcionira, svi korisnici GitHub-a u našoj organizaciji mogu vidjeti resurse i prijaviti se na podove, ali nemaju prava da ih mijenjaju.
izvor: www.habr.com